Looking at different scripts linking to Javascript and AJAX frameworks such as Scriptaculous, I noticed that it allows loading of particular parts of it by adding them in the following query string such as this:
<script type="text/javascript" src="scriptaculous.js?load=effects,builder"></script>
Looking at scriptaculous.js itself, it relied on some built-in functionality for that. I was unsuccessful in finding online a ready function to do exactly that, so inspired by this piece of code and borrowing the regex part of it, I wrote a function which grabs the additional parameters and allows using them in the Javascript:
function getJSvars
(script_name, var_name, if_empty
) {
var script_elements = document.getElementsByTagName(‘script’);
if(if_empty == null) {
var if_empty = ”;
}
for (a = 0; a < script_elements.length; a++) {
var source_string = script_elements[a].src;
if(source_string.indexOf(script_name)>=0) {
var_name = var_name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
var regex_string = new RegExp("[\\?&]"+var_name+"=([^&#]*)");
var parsed_vars = regex_string.exec(source_string);
if(parsed_vars == null) { return if_empty; }
else { return parsed_vars[1]; }
}
}
}
Usage of it is simple: if you have a Javascript which should parse some dynamic variables (such as user or account ID), you can include it right after the included Javascript like this:
<script type="text/javascript" src="script.js?var1=value1&var2=value2"></script>
instead of creating a server-side generated dynamic Javascript using PHP or other language. The values of variables like var1 can be retrieved like this:
var var1 = getJSvars(‘script.js’, ‘var1′);
You can also add a value as third parameter to output in case var1 is empty, but it is optional.
